Evaporator



Feb. 28, 1950 F. w. EMHARDT EVAPORATOR 3 Sheets-Sheet 1 Filed Dec. 6, 1945 Feb. 28, 1950 F. w. EMHARDT 2,499,302

EVAPORATOR Filed Dec. 6, 1943 v 3 Sheets-Sheet 2 Feb. 28, 1950 F. w. EMHARDT EVAPORATOR 3 Sheets-Sheet 3 Filed Dec.

gnguc/wbo b PM W Patented Feb. 1950 UNITED S TAT-ES AT E-NT 'zisas'oz EvAPoRAToR Fred W. Emhardt, Warren, Pa=., 'as'signor to Struthers Wells Corporation, Warren, Pa ia corporation of Maryland nppiieaii'tn December 6,1543, serial sesame Inen-t of the invention;

This invention relates to internally "heated evaporators and is particularly directed toan evaporator construction providing directed 'flow of the liquid to be evaporated about the'heating unit "of the evaporator. V g

'In liquid tubetype evaporators wherein the liquid being evaporatedis passed through tubes having the heating'medium external thereto, it is common practice to provide means for increasing the rate of flow of the liquid through the tubes for the purpose of increasing the rate of heat transfer to the'liquid, to'reduce'priming or foaming, and to reduce deposition of solids "on the "heating surfaces.

I have 'found that an increased, velocity of liquid flow in internally heated evaporators with similar advantagescan be obtained without the use of pumps, agitators orother power-driven devices by the construction er the invention which, in general, comprises the'provision of one for more shrouds between the heating u'nit and theshell of the evaporator to provide a vertical boiling passage including the heating unit and one or more downtfake passages between the shrouds and the shell of'theevaporator and a deflector above the top opening of the'boiling passage shaped to deflect liquid downwardly into the downflow passages. The heating units may comprise tube bundles or coils carrying a heating medium such as steam, oil, or the like, or

electric heating elements.

, A principal object of the invention, therefore, is the provision of an evaporator construction 6 Claims. ((11.159-28) whereby a high rate of liquid'circulation over the heating unit of an internally heated'evaporator will be maintained.

Other objects and advantages of the invention will be apparent from the following description of illustrative embodiments of the invention with particular reference to the accompanying drawings in which:

Fig. 1 is an elevation in partial section of a vertical evaporator embodying the principles of the invention; I

Fig. 2 is an elevation in partial section at right angle to the view oi Fig.1;

Fig. 3 is a transverse section on linef3- 3 of Fig. 2 with parts broken away;

Figs. 4, 5 and 6 are views, corresponding to Figs. '1, 2 and 3, respectively,-of-anotherembodi- ----Fig. '7 is an elevation ofahoriaontafevaporator embodying the principles oftheinvention;

Fig. 8 is an end view of the evaporator of Fig. Land H Fig. 9 is a've'rti'cal section'on line 9 9 ofFig. 7.

In Figs. 1 to 3, I0 is the shell of the evaporator, having in its lower portion a heating tube bundle ll, mounted in tube sheet I2 and supplied with the tubebiindle n heating fluid, such as steam, -Dowtherm or hot oil, through header I 3.

Extending aeross the shell on each side of the tube bundle are vertical shroud members l4, providing in conjunction with the walls of the shell a boiling passage "I 5 surroundingthe tube'bundle and downflow-passages ['6 between the shrouds and the shell. The upperportioiis 'of the shrouds 14 are bent inwardlyoveraportion' of the "tube define adownwardly and outwardly extending passage through which the vapors and entrained r liquids rnust'pfass travel from the boi1ing region l5 to the quiescent region l6.

By this constructionapositive rapid flow of liquid upwardly through theboiling passage I 5 is providedby the rising vapor-bubbles which carry with them a quantiity of liquid which is deflected back intothe downfiowfpassages l6 outside the confined heating unit, -Foamingand priming is eliminated by impingement of the boiling stream against the deflector I! and recirculation of the excess liquid intoa quiescent, non b'oiling region.

The increased positive liquid circulation past the heatingelernents results in increased cleanliness of the heatingsurface. All of these factors result in a "substantial increase-in evaporating efficiency. H p

In the construction of Figsg l-o, in which similar reference numeralsare used for corresponding structural elements, the heating unit comprises a plurality of vertical EoilsZ UefXtending between upper header zrane mwe; header '22.

Thedflfictor ll! is 'provid'edwlth gutters l'l' to drain deflected liquidback into'the downflow passages without dropping it through the vapor stream'passing out of the spaces between the deflectors and the 'u erend of the shrouds, thus .lrfnore efiectivelypreventing"entrainment of the "liquid.

regeneratin e1 aerate-renew mines. 7'49, bs ii i qe one ei the evaporator and the hoilirigpassagejlfa is'p'r'o 'ivided between saro g; 14 nd the side or the sha t-rifles "the passage '1 fifro'in thesideof-theshell.

I claim: 1. An evaporator comprising a. shell, a heating unit in the lower part of the shell, 9. vertical shroud member disposed alongside said heating unit and spaced from the wall of said shell, said shroud member having an inwardly and upwardly inclined wall portion at the upper edge thereof and a deflector member disposed above and closely adjacent to said heating unit and shroud member, said deflector having a downwardly and outwardly inclined wall portion overlying and in adjacent confronting relation with respect to said inwardly and upwardly inclined wall portion of the shroud member, said shroud member dividing said shell into boiling and nonboiling regions and said shroud and deflector providing a confined space above the boiling region, and said adjacent inclined wall portions of the shroud and deflector members definingv in cooperation a downwardly and outwardly directed passage connecting the confined space above the boiling region to the non-boiling region between the shroud and the shell while leaving ample space for vapors to rise in the shell after egress from said passage.

2. An evaporator comprising a shell, a heating unit in the lower part of the shell, a substantially vertical shroud member disposed alongside said heating unit and spaced from the wall of said shell thereby dividing said shell into boiling and non-boiling regions, said shroud member having an upwardly and inwardly inclined wall portion at the upper end thereof, and a deflector member disposed above and closely adjacent to said heating unit and shroud member, said deflector having a downwardly and outwardly inclined wall portion overlying and in adjacent confronting spaced relationship to said inclined wallportion of said shroud member and with its lowermost edges lying in the region of the horizontal plane through the top of the heating unit and at least substantially nearer said plane than the upper end of said shroud member, the downwardly and outwardly inclined wall portion of said deflector being adapted by its relative disposition to said inclined wall portion of the shroud member to cooperate therewith in defining a restricted positive path capable of directing a rapidly moving fluid stream from said boiling region downwardly and outwardly into said non-boiling region, and said shroud and deflector providing a confined space above said boiling region.

3. An evaporator comprising a shell, a heating unit in the lower part of the shell, a first vertical shroud member disposed alongside said heating unit and spaced from the wall of said shell, a second vertical shroud member alongside said heating unit and spaced from the wall of said shell on the opposite side of said heating unit from said first shroud member, said shroud members having inwardly and upwardly inclined wall portions at the upper edges thereof extending in converging directions above said heating unit, a deflector member disposed above and closely adjacent to said heating unit and shroud members, said deflector member having opposite downwardly and outwardly inclined wall portions overlying and in adjacent confronting spaced rela tion with said inwardly and upwardly inclined wall portions of said shroud members, said shroud members dividing said shell into a boiling region and non-boiling regions, said shroud and deflector members providing a confined space above the heating unit, and said inclined wall portions of'the shroud members defining in cooperation with the adjacent inclined portions of the deflector member downwardly and outwardly directed passages connecting the confined space above the heating unit to the non-boiling regions between the shroud members and the shell while leaving ample space for vapors to rise in the shell after egress from said passage.

4. An evaporator as defined in claim 3 wherein the opposite downwardly and outwardly inclined wall portions of said deflector member which are overlying and in adjacent confronting spaced relation with said inwardly and upwardly inclined wall portions of said shroud member are substantially parallel thereto.

5. An evaporator as defined in claim 3 wherein the deflector has intermediate its downwardly and outwardly inclined wall portions and substantially aligned with the center line of said heating unit a downwardly extending portion V-shaped in transversesection formed by opposite inwardly sloping and converging surfaces and adapted to serve as a divider for an up-rising fluid stream in said boiling region.

6. An evaporator comprising a shell, a heating unit in the lower part of the shell, a vertical shroud member disposed alongside said heating unit and spaced from the walls of said shell, and defining therewith a non-boiling region and a boiling region including said heating unit, said shroud member having an upwardly inclined wall portion at the upper edge thereof extending inwardly of the boiling region, and a deflector member extending from the wall of said shell adjacent the boiling region and disposed above and closely adjacent to said heating unit and said shroud member, said deflector having a downwardly inclined wall portion extending outwardly of said boiling region into said non-boiling region and in overlying and adjacent confronting spaced relation with said inwardly and upwardly inclined wall portion of the shroud member, said shroud and deflector members providing a confined space above said heating unit, and said adjacent inclined wall portions of the shroud and deflector members defining in cooperation a downwardly inclined restricted passage connecting the confined space above the heating unit with the nonboiling region between the shroudand shell while leaving ample space for vapors to rise in the shell after egress from said passage.

FRED W.. EMHARDT.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 519,969 Rayner May 15, 1894 751,998 Rafeau Feb. 9, 1904 807,586 Voight Dec. 19, 1905 1,028,086 Faller May 28, 1912 1,131,738 Row Mar. 16, 1915 1,166,539 Olson Jan. 4, 1916 1,253,411 Melchior Jan. 15, 1918 1,420,366 Davis June 20, 1922 1,439,278 Voight Dec. 19, 1922 1,781,764 Peperkorn Nov. 18, 1930 FOREIGN PATENTS Number Country Date 528,890 Great Britain Nov. 8, 1940 

